US2280571A - Furnace - Google Patents

Description

April 21, 1942.

J. DIONISOTTI 2,280,571

FURNACE Filed Aug. 29, 1939 s Sheets-Sheet 1 April 1942- J. biomso'm 2,280,571

FURNACE Filed Aug. 29, 1939 s Sheets-Sheet 5 Fig.7

v I l 47 46 52 54 v inner/a5 u. Zia/7239 24;

Patented Apr. 21, 1942 FURNACE Joseph Dionisotti, Monthcy, Valais, Switzerland Application August 29, 1939, Serial No. 292,498

In Switzerland September 15,1938 7 4 Claims.

This invention relates to a furnace or kiln, more especially a lime kiln, comprising a device for mixing the material such as limestone and solid fuel fed to the furnace and for the evacuation of gases, and a furnace proper, characterized by the fact that the lower end of the mixing apparatus is arranged inside the furnace proper, the section of the charging and discharging openings of the furnace being small relatively to the middle section of the furnace, the whole being arranged so that during operation of said furnace there is always a layer of material resting on a part of the wall of the furnace so as to protect said part against heat and against thefriction of the material introduced.

Examples of constructions of furnaces accord ing to the invention are shown by way of example in the accompanying drawing in which:

Fig. l is a vertical cross section of one construction partly in elevation at the lower portion.

Fig. 2 is a fragmentary sectional view along line 22 of Fig. 1, the free section of the narrow part being at its maximum.

Fig. 3 is a similar section the narrow part being partially obstructed and the mixed lines showing the axes of the rods which are not shown in the drawings.

Fig. 4 is a section on line 44 of Fig. 1.

Fig. 5 is a section on line 5--5 of Fig. 1.

Fig. 6 is a sectional View of a modification.

Fig. 7 is a section of the upper end of thefirst construction.

The kiln shown in Figs. 1 to 7 comprises a furnace proper having an upper chamber I fed by a mixing and feeding device 25, and a lower chamber 2 connected through a narrow part 3 the free section of which can be varied by means of a device comprising rods 4 arranged radially around the circular part 3. adapted to be pushed into or withdrawn from the part 3 so as to reduce or increase the free section of the latter, thus resulting in the reduction or increase of the diameter of the hot zone 30 in the upper chamber I in which the material is heated, whereby the output of the kiln is regulated.

Each rod 4 is provided at one of its ends with a thin part 5 co-operating with the similar parts of adjacent rods to regulate the free section of the part 3 and each rod is provided at its other end with a handle 6 which can be moved and a removable pin I limiting its inward movement. In addition, each rod is provided with a series of holes by which the position of the rod relatively i The rods 4 are part of the kiln.

to the wall of the furnace can be fixed, said holes being intended to receive successively the corresponding pin. Each rod 4 passes through two sleeves 3| and 32 connected by rods 33 the sleeves 3I and 32 beingfitted in corresponding sleeves 34 and 35 fixed to the masonry of the kiln. If the end 35 of a' rod 4 is bent it is sufficient to withdraw the sleeves 3I and 32 connected by the rods 33; in order to be able to remove the rod and repairit.

The kiln has, on the one hand, inside the upper and lower chambers a passage for air under pressure, the air previously heated being intended to increase the heat for raising the temperature in the'upper chamber, and, on the other hand, around the-lower chamber a circular channel S'connected to the outside by means of conduits I0 and communicating with the interior of said chamber 2 through openings II, the channel 9 being adapted to supply air for cooling the material and for burning the gases-in the chamber I. Additional water cooling pipes 8 are pro vided near the upper part of the lower chamber. The wall of the chamber 2 is widened at I2 to facilitate the descent of the material which is at the periphery of thekiln; The latter is provided with an open-work ventilation shaft I3 arranged axially and supported by means of sup- ,ports I4 and clamps I5 and I6 pressing against the wall of the chamber 2.

The ventilation shaft I3 through which air may be introduced and dust may be removed is provided with a circular baffle I1 adapted to check the fall of material moving in the central The diameter of said bafile may be variable and it is intended to co-operate with the widened part I2 so as to ensure as far as possible the simultaneous descent of the whole mass of material which at any given instant is at the same level. At the lower end of the upper chamber I are arranged openwork pockets 31 for discharging dust and for introducing air. Said pockets are fixed to the side wall of the kiln and are connected to a common channel 38 surrounding the latter, said channel communicating with the outside through conduits 39 and 40 connected to a source for introducing air therethrough. The dust is removed by means of the mixing and feeding device hereinafter described e 42 and the lower part 43 of the wall is made to widen progressively from the bottom upwards. The chamber I is constructed in such a way that during operation of the furnace a layer of material 44 constantly rests on a part of the wall so as to protect the latter against heat and against the friction of said material, thus avoiding wear and deterioration of said wall.

A mixing and feeding device comprising two telescoping elements 45 and 46 extends into the top of the kiln shown, the upward movement of the lower element 45 being controlled by cables 41' operated by means of pulleys 48. The position of the tube 45 enables the height and width of the hot zone to be increased or reduced owing to the increase or reduction of the distance between the lower end of the tube and the bottom of the chamber I, the consequence of which is to increase or reduce the production of the material, for example lime. The wall of the lower end of the element 45 is cooled by a water channel 49.

The combustion gases are discharged through an apparatus 50 comprising at least two telescoping elements 5| and 52 the walls of which are provided with holes 53. The combustion gases are partly used for heating the material falling in the feeding mixer 25 and are partly discharged through a conduit 54 and used outside the kiln. The part of the hot gases discharged through the conduit 54 is regulated by varying the height of the element 5| which can be moved by means of a cable 55 actuated by a shaft 56.

The upper end of the chamber l is provided with a shoulder 21 on which bricks 28 are arranged. The mouth 26 of said chamber is in proportion to the dimensions of said bricks.

At the lower end of the shaft I3 is fitted a cone or bell 18 over which the material leaving the kiln moves. The slope of the cone can be modified according to whether the material at the periphery of the kiln is to be removed more quickly than the material at the axial part or vice versa. Parts l9 constructed, for example, of sheet metal and forming radial channels 20 are fixed to the bell I8. Each of the channels 20 terminates in a conduit 2| at the lower end of which is arranged a bucket wheel 22. The lower ends of the channels 20and the wheels 22 are supported on suitable supports 2|. Each of the wheels 22 which can be rotated causes the niaterial leaving the corresponding conduit to fall into a funnel 23 whence it passes into a conveyor 24. The output of any particular conduit 2| can be varied by varying the speed of rotation of the corresponding wheel 22.

I claim:

1. A lime kiln comprising in combination, a furnace proper having an upper enlarged combustion chamber and a lower air chamber, a throat of restricted cross section connecting said combustion chamber with said air chamber, a charging opening of restricted cross section in the upper portion of said combustion chamber, adjustable means in said charging opening for introducing a mixture of limestone and solid fuel into said combustion chamber, said adjustable means adapted to extend into said combustion chamber to control the heat zone in said chamber, second means in said charging opening for discharging the gases while recuperating the heat, the central portion of said combustion chamber being of greater diameter than the upper and lower portions of said chamber, whereby during operation of said furnace a layer of material collects around the inner wall of the combustion chamber to protect said wall against heat and against friction with the mixture introduced through said charging opening, and means for varying the cross sectional area of said throat to regulate the discharge of materials from said combustion chamber.

2. A lime kiln as claimed in claim 1 including means in said combustion chamber for discharging dust from the latter.

3. In a lime kiln of the type including a combustion chamber, an air chamber below said combustion chamber, and a throat of restricted cross section connecting said chambers, the improvement which consists in a device for varying the cross sectional area of said throat comprising a series of radial rods slidably mounted in openings in the wall of said kiln adjacent said throat, said rods adapted to be pushed inwardly and outwardly tocontrol the discharge of materials from said combustion chamber.

4. A lime kiln comprising an enlarged combus tion chamber, air inlet opening of restricted cross section in the upper portion of said combustion chamber, a pair of vertically disposed tubular telescoping members in said inlet opening for introducing a mixture of limestone and solid fuel into said combustion chamber, one of said members being slidably adjustable within the other and adapted to extend into said combustion chamber to control the heat zone therein, means for adjusting the position of said slidable member, means in said members for discharging the gases from said combustion chamber including a pair of telescoping members, the inner member being provided with radial openings and means for regulating the sizes of said openings.

JOSEPH DIONISOTTI.

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